/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <AK/FlyString.h>
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/StringView.h>
#include <AK/Vector.h>

#ifndef KERNEL
#    include <inttypes.h>
#endif

#ifdef KERNEL
extern "C" char* strstr(const char* haystack, const char* needle);
#endif

namespace AK {

String::String(const StringView& view)
{
    if (view.m_impl)
        m_impl = *view.m_impl;
    else
        m_impl = StringImpl::create(view.characters_without_null_termination(), view.length());
}

bool String::operator==(const FlyString& fly_string) const
{
    return *this == String(fly_string.impl());
}

bool String::operator==(const String& other) const
{
    if (!m_impl)
        return !other.m_impl;

    if (!other.m_impl)
        return false;

    if (length() != other.length())
        return false;

    return !memcmp(characters(), other.characters(), length());
}

bool String::operator==(const StringView& other) const
{
    if (!m_impl)
        return !other.m_characters;

    if (!other.m_characters)
        return false;

    if (length() != other.length())
        return false;

    return !memcmp(characters(), other.characters_without_null_termination(), length());
}

bool String::operator<(const String& other) const
{
    if (!m_impl)
        return other.m_impl;

    if (!other.m_impl)
        return false;

    return strcmp(characters(), other.characters()) < 0;
}

bool String::operator>(const String& other) const
{
    if (!m_impl)
        return other.m_impl;

    if (!other.m_impl)
        return false;

    return strcmp(characters(), other.characters()) > 0;
}

String String::empty()
{
    return StringImpl::the_empty_stringimpl();
}

String String::isolated_copy() const
{
    if (!m_impl)
        return {};
    if (!m_impl->length())
        return empty();
    char* buffer;
    auto impl = StringImpl::create_uninitialized(length(), buffer);
    memcpy(buffer, m_impl->characters(), m_impl->length());
    return String(move(*impl));
}

String String::substring(size_t start, size_t length) const
{
    if (!length)
        return {};
    ASSERT(m_impl);
    ASSERT(start + length <= m_impl->length());
    // FIXME: This needs some input bounds checking.
    return { characters() + start, length };
}

StringView String::substring_view(size_t start, size_t length) const
{
    ASSERT(m_impl);
    ASSERT(start + length <= m_impl->length());
    // FIXME: This needs some input bounds checking.
    return { characters() + start, length };
}

Vector<String> String::split(char separator, bool keep_empty) const
{
    return split_limit(separator, 0, keep_empty);
}

Vector<String> String::split_limit(char separator, size_t limit, bool keep_empty) const
{
    if (is_empty())
        return {};

    Vector<String> v;
    size_t substart = 0;
    for (size_t i = 0; i < length() && (v.size() + 1) != limit; ++i) {
        char ch = characters()[i];
        if (ch == separator) {
            size_t sublen = i - substart;
            if (sublen != 0 || keep_empty)
                v.append(substring(substart, sublen));
            substart = i + 1;
        }
    }
    size_t taillen = length() - substart;
    if (taillen != 0 || keep_empty)
        v.append(substring(substart, taillen));
    return v;
}

Vector<StringView> String::split_view(const char separator, bool keep_empty) const
{
    if (is_empty())
        return {};

    Vector<StringView> v;
    size_t substart = 0;
    for (size_t i = 0; i < length(); ++i) {
        char ch = characters()[i];
        if (ch == separator) {
            size_t sublen = i - substart;
            if (sublen != 0 || keep_empty)
                v.append(substring_view(substart, sublen));
            substart = i + 1;
        }
    }
    size_t taillen = length() - substart;
    if (taillen != 0 || keep_empty)
        v.append(substring_view(substart, taillen));
    return v;
}

ByteBuffer String::to_byte_buffer() const
{
    if (!m_impl)
        return nullptr;
    return ByteBuffer::copy(reinterpret_cast<const u8*>(characters()), length());
}

Optional<int> String::to_int() const
{
    return StringUtils::convert_to_int(view());
}

Optional<unsigned> String::to_uint() const
{
    return StringUtils::convert_to_uint(view());
}

String String::number(unsigned long long value)
{
    int size;
    char buffer[32];
    size = sprintf(buffer, "%llu", value);
    return String(buffer, size);
}

String String::number(unsigned long value)
{
    int size;
    char buffer[32];
    size = sprintf(buffer, "%lu", value);
    return String(buffer, size);
}

String String::number(unsigned value)
{
    char buffer[32];
    int size = sprintf(buffer, "%u", value);
    return String(buffer, size);
}

String String::number(long long value)
{
    char buffer[32];
    int size = sprintf(buffer, "%lld", value);
    return String(buffer, size);
}

String String::number(long value)
{
    char buffer[32];
    int size = sprintf(buffer, "%ld", value);
    return String(buffer, size);
}

String String::number(int value)
{
    char buffer[32];
    int size = sprintf(buffer, "%d", value);
    return String(buffer, size);
}

String String::format(const char* fmt, ...)
{
    StringBuilder builder;
    va_list ap;
    va_start(ap, fmt);
    builder.appendvf(fmt, ap);
    va_end(ap);
    return builder.to_string();
}

bool String::starts_with(const StringView& str) const
{
    if (str.is_empty())
        return true;
    if (is_empty())
        return false;
    if (str.length() > length())
        return false;
    return !memcmp(characters(), str.characters_without_null_termination(), str.length());
}

bool String::starts_with(char ch) const
{
    if (is_empty())
        return false;
    return characters()[0] == ch;
}

bool String::ends_with(const StringView& str, CaseSensitivity case_sensitivity) const
{
    return StringUtils::ends_with(*this, str, case_sensitivity);
}

bool String::ends_with(char ch) const
{
    if (is_empty())
        return false;
    return characters()[length() - 1] == ch;
}
String String::repeated(char ch, size_t count)
{
    if (!count)
        return empty();
    char* buffer;
    auto impl = StringImpl::create_uninitialized(count, buffer);
    memset(buffer, ch, count);
    return *impl;
}

bool String::matches(const StringView& mask, CaseSensitivity case_sensitivity) const
{
    return StringUtils::matches(*this, mask, case_sensitivity);
}

bool String::contains(const String& needle) const
{
    if (is_null() || needle.is_null())
        return false;
    return strstr(characters(), needle.characters());
}

Optional<size_t> String::index_of(const String& needle) const
{
    if (is_null() || needle.is_null())
        return {};

    const char* self_characters = characters();
    const char* result = strstr(self_characters, needle.characters());
    if (!result)
        return {};
    return Optional<size_t> { result - self_characters };
}

bool String::equals_ignoring_case(const StringView& other) const
{
    return StringUtils::equals_ignoring_case(view(), other);
}

int String::replace(const String& needle, const String& replacement, bool all_occurences)
{
    if (is_empty())
        return 0;

    Vector<size_t> positions;
    size_t start = 0, pos;
    for (;;) {
        const char* ptr = strstr(characters() + start, needle.characters());
        if (!ptr)
            break;

        pos = ptr - characters();
        positions.append(pos);
        if (!all_occurences)
            break;

        start = pos + 1;
    }

    if (!positions.size())
        return 0;

    StringBuilder b;
    size_t lastpos = 0;
    for (auto& pos : positions) {
        b.append(substring_view(lastpos, pos - lastpos));
        b.append(replacement);
        lastpos = pos + needle.length();
    }
    b.append(substring_view(lastpos, length() - lastpos));
    m_impl = StringImpl::create(b.build().characters());
    return positions.size();
}

String String::trim_whitespace(TrimMode mode) const
{
    auto is_whitespace_character = [](char ch) -> bool {
        return ch == '\t'
            || ch == '\n'
            || ch == '\v'
            || ch == '\f'
            || ch == '\r'
            || ch == ' ';
    };

    size_t substring_start = 0;
    size_t substring_length = length();

    if (mode == TrimMode::Left || mode == TrimMode::Both) {
        for (size_t i = 0; i < length(); ++i) {
            if (substring_length == 0)
                return "";
            if (!is_whitespace_character(characters()[i]))
                break;
            ++substring_start;
            --substring_length;
        }
    }

    if (mode == TrimMode::Right || mode == TrimMode::Both) {
        for (size_t i = length() - 1; i > 0; --i) {
            if (substring_length == 0)
                return "";
            if (!is_whitespace_character(characters()[i]))
                break;
            --substring_length;
        }
    }

    return substring(substring_start, substring_length);
}

String escape_html_entities(const StringView& html)
{
    StringBuilder builder;
    for (size_t i = 0; i < html.length(); ++i) {
        if (html[i] == '<')
            builder.append("&lt;");
        else if (html[i] == '>')
            builder.append("&gt;");
        else if (html[i] == '&')
            builder.append("&amp;");
        else
            builder.append(html[i]);
    }
    return builder.to_string();
}

String::String(const FlyString& string)
    : m_impl(string.impl())
{
}

String String::to_lowercase() const
{
    if (!m_impl)
        return {};
    return m_impl->to_lowercase();
}

String String::to_uppercase() const
{
    if (!m_impl)
        return {};
    return m_impl->to_uppercase();
}

bool operator<(const char* characters, const String& string)
{
    if (!characters)
        return !string.is_null();

    if (string.is_null())
        return false;

    return __builtin_strcmp(characters, string.characters()) < 0;
}

bool operator>=(const char* characters, const String& string)
{
    return !(characters < string);
}

bool operator>(const char* characters, const String& string)
{
    if (!characters)
        return !string.is_null();

    if (string.is_null())
        return false;

    return __builtin_strcmp(characters, string.characters()) > 0;
}

bool operator<=(const char* characters, const String& string)
{
    return !(characters > string);
}

bool String::operator==(const char* cstring) const
{
    if (is_null())
        return !cstring;
    if (!cstring)
        return false;
    return !__builtin_strcmp(characters(), cstring);
}

StringView String::view() const
{
    return { characters(), length() };
}

}